This invention relates to the load clipping devices for cranes and more particularly to the crane remote controlled load clipping and load accidental release prevention devices.
The various types of the load clipping devices for crane hook are well known. The release of the heavy and large size (tall) construction structures with the small basis square, lifted by construction crane, is a difficult operation, requiring the high qualification of the crane operator and rigger. In order to provide effective and safety load release, the most crane hooks have supplementary equipment. For example, the hook by U.S. Pat. No. 5,688,009 includes the longitudinally extending frame member which is attached to a moveable arm of the material handling lift. A longitudinally extending probe is positioned below and parallel to the frame member. An end frame member is positioned between the upper frame member and the probe. A pusher arm is mounted for movement along the probe to urge items being carried by the probe to new predetermined positions.
A probe, which in this embodiment is a cylindrical rod, is positioned below and parallel to the frame member. The frame member and probe are joined together by an end assembly. A moveable arm is connected to the frame member by a pair of mounting plates. A longitudinally extending screw is journaled by bearings within the frame member. A motor is mounted on the end assembly and includes an output shaft, which mounts a pulley. Another pulley is operatively connected to the screw. A drive belt extends between the pulleys. Operation of the motor drives or rotates the screw. The screw is an Acme screw. The device also includes a pusher arm. The pusher arm has a pusher plate. A lower end of the pusher plate is complementary with the circumference of the cylindrical probe. The pusher arm depends on a pusher block which in turn is carried by the screw. The pusher block defines a threaded opening which mates with threads defined by the screw.
In operation, the moveable arm of the power lift material handling apparatus is positioned where, for example, the free end of the probe receives, for instance, the center openings of a plurality of paper rolls. The plurality of paper rolls are aligned along the probe. When in the initial position, the pusher arm is generally moved to its rearward position, adjacent the frame end. This is accomplished by energizing the motor and rotating the screw. The threaded engagement with the screw moves the pusher block and the attached pusher arm to the desired position. The arm can then be moved to another position. At that time, all of the rolls may be released from the probe by moving the pusher arm to the left.
Such devices can not provide the safe lifting of the large-size (tall) loads, having oscillation (swaying) effect, considering the presence of the open (unlocking) portion of the load clipping C-hook.
Another device by the U.S. Pat. No. 3,971,478 comprises a load trolley moving on tracks fitted to the steel bridge of the overhead crane. On top of the load trolley there is a circular track on which there is a rotatable crab provided with a swivelling mechanism, hoist mechanism, a lifting beam provided with C-shaped claws, and a tilting mechanism for the beam and claws. The load carrier system includes the C-shaped claws featuring the tilting movement, and is equipped with from one to four lifting magnets and lifting hooks, the lifting beam assembly being suspended on the auxiliary beam by means of linking pin members. These pin members are for the dismantling of the lifting load, e.g. the handling of rolled products stored on racks; in this case the load is taken by means of a hook. The mentioned device also comprises the pairs of ropes 1, as well as two other ropes being provided for lifting and lowering the auxiliary load beam.
The ropes have their starting ends secured to the frame of the rotatable crab and their opposite ends, after being entrained over balance pulleys, which are located with their axis of rotation passing through the longitudinal center-line of the auxiliary beam, are directly entrained over guide pulleys and finally are wound round the section threaded with double thread of the drums which are mounted centrally on the rotatable crab. Each of the balance pulleys includes multiple sheaves to receive the respective pair of ropes. The starting ends of the cables are secured on the frame of the rotatable crab and their opposite ends after being entrained on balance pulleys installed on the auxiliary beam with their axis of rotation normal to the longitudinal center-line of the auxiliary beam, and then are guided by three pairs of guiding pulleys, being then normally brought to the same drums provided with double thread sections where the ropes are finally wound. Also the lifting beam is provided with C-shaped claws, the latter being attached by the wire ropes arranged at an inclined pattern. The starting ends of the wire ropes are normally brought to the same drums after being entrained on three pairs of guide pulleys. The final ends of the ropes are entrained on an assembly of balance pulleys, whose center of rotation is located sidewise at a distance from the longitudinal center-line of the lifting beam; however, the mentioned assembly is situated in height as nearly as possible to the horizontal plane passing through the centers of rotation of the balance pulleys secured to the auxiliary beam. The ropes are afterwards entrained over the other guide pulleys and are finally wound around the section of the drum provided with double threading of the tilting mechanism located on the rotatable crab. The assembly of balance pulleys is attached by means of hinged attaching members sidewise at a distance from the longitudinal center-line of the lifting beam.
The electrical control cab is suspended on the rotatable crab by means of a steel structure which is provided inside with stairs for the direct access thereto of crane operators from the control cab to the rotatable crab.
Such devices are complex and expensive.
Some crane hooks have a pivotable closure member (locking lever), as it is described, for example, in the U.S. Pat. No. 5,765,891, wherein the lever can be retracted into the hook opening thereby unlocking the hook. The crane hook by the mentioned patent includes a bridge portion of the shank, which extends across a slot between the shank portions so as to connect the two shank portions to each other and to divide the slot into an upper slot part and a lower slot part. The upper slot part is provided with an anchoring member extending transversely between the two shank portions for securely anchoring an end link of the hoisting chain to the shank of the hook. The lower slot part has an insertion opening, into which a desired link of the hoisting chain can be inserted and be displaced into the centrally located position adjacent to said bridge portion and the recessed seating surfaces are located at the lower slot part adjacent to the bridge portion and are oriented so that the engagement link, when engaging the recessed seating surfaces, projects transversely away from the upper shank so as to form a loose, non-loaded loop of the hoisting chain between the anchored end link and the engagement link.
These devices require the use of a non-standard crane hook, having a complex and expensive modernization.
Thus, there is a great need in the art for a crane load clipping device, providing not complex remote controlled load clipping and load accidental release prevention devices.
Accordingly, several objects and advantages of the present invention are to provide the cranes with the remote controlled load clipping devices.
It is another object of the invention to increase the safety of the lifting processes.
It is still another object of the invention to provide the load accidental release prevention.
It is further object of the invention to decrease the rigging operation time.
It is still further object of the invention to increase the efficiency of the tall building material (construction) installation.